Through the support of a Phase I SBIR we have successfully demonstrated the use of a novel and innovative proprietary technology for the identification of genes under the transcriptional control of the tumor suppressor p53. This technology has several distinct advantages over current methods used in the recovery of DNA sequences, such as library screening and PCR. We have used this technology to isolate two genes which are expressed in prostate, testis, colon, and ovarian epithelial tissue. The immediate objectives of this proposal are 1) to develop an in vivo biological assay to evaluate the p53-responsiveness of these genes and 2) to determine if aberrant expression of these genes is associated with uncontrolled proliferation and anchorage independent growth. We hypothesize that if p53 regulated genes function at or near the convergence point of multiple signal transduction pathways, they may be highly specific markers of the proliferative status of a cell. Thus, their inappropriate expression may be significant in the development and progression of cancer. The isolation and characterization of these genes may lead to the identification of specific diagnostic and prognostic indicators for a number of cancers, and they may have a potential for the development of novel therapeutic reagents. PROPOSED COMMERCIAL APPLICATION: Current available cancer markers do not provide adequate diagnostic and prognostic information. The most important commercial application of this research would be the development of highly specific tumorigenic markers which could be used in early diagnosis, and in the clinical evaluation of cancer patients.